Quitting smoking, getting fit or losing weight are all easier if your partner is on the same health kick, new research suggests.

People whose partner stops smoking, loses weight or gets more active are far more likely to be successful in adopting healthier habits themselves, according to a study that compared people trying to get healthy at the same time as their partner or separately.

By contrast, living with somebody who is not overweight, does not smoke or plays sport regularly does not appear to help you change your own behaviour, according to the study published in the journal JAMA Internal Medicine. But if your spouse or partner manages to turn over a new leaf, it improves your chances of doing so too.

A large body of evidence suggests that people adopt the sorts of behaviour they see around them – and in particular that of their spouses. Couples tend to have similar drinking, smoking, physical activity and eating patterns. Some of the similarity, say the researchers, “appears to be the result of assortative mating, with individuals selecting mates with behaviours similar to their own”.